It is desirable, in certain applications, to make three dimensional measurements at very high speed, especially with fast moving or fast shape changing objects. To make three dimensional measurements in the prior art, two methods have been used as follows:
1. A succession of patterns were projected onto the object being measured. Corresponding to each of the light patterns projected onto the object, a photograph or TV picture was taken. Both digital and analog patterns were used. PA1 2. A succession of pulses of light were transmitted and a gated receiver integrated the light reflected from the object to be measured. The gating was done in a time-coded manner to encode distance to the object surface as a function of the travel time of the light.
Since both methods involve a sequence of events that have time durations that may accumulate to a period of time too great to make an adequate measurement, the present invention provides two methods to improve the state of the art. The limitations of the prior art come from the time it takes to change the projection of one pattern to another and the time it takes to record the reflected light and prepare for a subsequent recording.
The present invention provides methods for allowing events on both the projector and receiver sides of the measurement system to operate in parallel in order to reduce the overall time of measurement. The methods can also be applied, in part, to implement other prior art techniques such as separating the transmitted patterns by the frequency of radiation and parallel gating of received energy from a single projected pulse.